3D-bioprinttaustahnat selluloosan nanofbrilleihin ja kolloidisiin ligniinipartikkeleihin perustuen

Three-dimensional (3D) bioprinting has been utilized for decades, and today its popularity is up surging. 3D bioprinting is based on the use of the natural, non-toxic, and tissue-mimicking bio-materials which are extruded in the form of bioinks to generate different structures layer-by-layer, from a simple cylinder to the shape of an ear. This method is gaining popularity in the field of regenerative medicine in which the focus is in regenerating and replacing injured tissues and organs. However, the major obstacles in the utilization of the current biomaterials are their insufficient properties, especially in the case of the mechanical strength. Therefore, new materials, hybrid materials, and material composites need to be developed. In this Master’s thesis, the novel CLP-CNF-alginate bioink compositions were prepared with the cellulose nanofibril (CNF) concentrations of 2.5 wt%, alginate concentrations of 0.5 wt%, and colloidal lignin nanoparticle (CLP) concentrations relative to the dry weight of CNF. The rheological properties of these bioinks were measured through the dynamic viscosity and amplitude sweep measurements, whereas the printability of the bioinks was tested in 3D bioprinting. This was followed by the compression tests and the evaluation of the hydrogels in different storage conditions. These various stability tests included freeze-drying, re-wetting, humidity chamber, salt-water solution, and free-standing at room temperature. The addition of CLPs into the CNF-alginate hydrogel offered many advantages. Most importantly, the existence of CLPs enhanced the printability and structural stability of the hydrogels directly after 3D bioprinting. On the other hand, the addition of CLPs increased the dimensional stability of the CLP-CNF-alginate hydrogels in high humidity and salt-water solutions. Nevertheless, dissolution in the salt-water solution, fast drying in the room air, and the non-toxicity of these hydrogels with the degradation rates inside the human body require further research. However, these multiple intrinsic properties of the CLP-CNF-alginate hydrogels make them a multifunctional material for the regenerative medicine.3D-bioprinttausta on hyödynnetty vuosikymmeniä, mutta nykyään sen suosio on räjähdysmäisessä kasvussa. 3D-bioprinttauksessa käytetään luonnonmukaisia, myrkyttömiä ja kudoksia jäljitteleviä biomateriaaleja, jotka ruiskutetaan biotahnojen muodossa, kerros kerrokselta, muodostamaan erilaisia rakenteita, aina yksinkertaisesta lieriöstä korvanmuotoisiin rakenteisiin asti. Menetelmä on suosittu regeneroivassa lääketieteessä, jossa keskitytään vahingoittuneiden tai sairaiden kudosten sekä elinten korvaamiseen. Suurimmat haasteet nykyisten biomateriaalien hyödyntämisessä liittyvät niiden riittämättömiin ominaisuuksiin, erityisesti mekaanisten ominaisuuksien osalta. Tämän vuoksi uusia materiaaleja, hybridimateriaaleja ja materiaalikomposiitteja on tärkeä kehittää. Tässä diplomityössä valmistettiin uusia CLP-CNF-alginaatti -biotahnoja, jotka sisälsivät 2,5 p-% nanofibrilloitua selluloosaa (CNF), 0,5 p-% alginaattia ja kolloidisia ligniinipartikkeleita (CLPs) CNF-kuitujen kuivapainon mukaisesti. CLP-CNF-alginaatti -biotahnojen reologiset ominaisuudet mitattiin dynaamisten viskositeetti- ja amplitudimittausten avulla. Biotahnojen printattavuutta sen sijaan tutkittiin 3D bioprinttauksessa, mitä seurasivat kompressiotestit ja varastointimittaukset. Varastointimittauksiin kuuluivat hydrogeelien kylmäkuivaus, uudelleen kostutus sekä säilytys kosteuskammiossa, suolavesiliuoksessa ja huoneilmassa. Ligniinipartikkeleiden lisäys CNF-alginaatti -hydrogeeliin tarjosi monia etuja. Ligniinipartikkelit paransivat erityisesti hydrogeelien printattavuutta sekä rakenteen stabiilisuutta 3D bioprinttauksen jälkeen. Ligniinipartikkeleiden lisäys kasvatti myös hydrogeelien rakenteellista pysyvyyttä korkeassa kosteudessa ja suolaliuoksessa. Hydrogeelien liukeneminen suolaliuoksessa, nopea kuivuminen huoneilmassa sekä myrkytön hajoaminen elimistössä vaativat kuitenkin lisätutkimusta. Yleisesti ottaen CLP-CNF-alginaatti -hydrogeelit ovat monikäyttöisiä materiaaleja regeneroivan lääketieteen tarkoituksiin

A multi-criteria decision-making framework and analysis of vegetable oils to produce bio-based plastics

In the present paper, the suitability of the selected oilseeds, their corresponding vegetable oils, and few other raw materials to produce bio-based plastics was evaluated by constructing a novel criteria-based framework for Multi-Criteria Decision-Making (MCDM) analysis with a focus on the criteria of chemical functionality, sustainability, production quantity, cost, and market availability. Qualitative, semi-quantitative, and quantitative data was utilized as a base for the criteria, for which a 1–5–9 scaling technique was developed to convert the hybrid starting data into the quantitative form, when required. Additionally, two varying sets of starting data, four scenarios with differing weights of importance, as well as two different MCDM techniques, namely Technique for Order Preference and Similarity to Ideal Solution (TOPSIS) and Simple Additive Weighting (SAW), were used as a form of sensitivity analysis. The MCDM results were influenced by the dissimilar algorithm of TOPSIS and SAW techniques, resulting in different level of accuracy and a phenomenon of rank reversal, together with the developed MCDM framework in terms of the utilized data types, scaling technique, assumptions to treat data uncertainty as well as the selected criteria and scenarios. Regardless of the different starting data sets, scenarios, and MCDM techniques utilized for the MCDM analysis, tall, linseed, soybean, and palm oil were identified as the most suitable and palm kernel, coconut, and sunflower oil as the least suitable raw materials with their feature trade-offs to produce bio-based plastics. The MCDM results of the present paper can be treated as a guidepost targeted for diverse actors in the early stage of the bio-based plastics’ value chain with varying point-of-views. Further, in the future, the novel MCDM framework can be of relevant significance in analysing the features of various raw materials to produce bio-based plastics.Peer reviewe

Towards Sustainable and Circular Practices with Plastics: Exploring the Potential of Law and Governance Tools Based on Holistic and Harmonized Life Cycle Assessment

The journal editor gave permission to self-archive Version of Record, editor's contact info: Tomi Tuominen ([email protected])Low recycling rates, varying recycling possibilities, and accumulation in nature are issues commonly associated with plastics. Promoting sustainable and circular practices with plastics requires the awareness and engagement of all the stakeholders from public to private actors operating in the plastics value chain. Notwithstanding the existence of several public laws and policies aiming to regulate plastic production and use in order to make the whole value chain more circular, most of these instruments target only specific stakeholder groups (e.g. plastics producers) and affect only certain types of plastics. Even if some private law and governance instruments, such as certifications (including intellectual property rights) and eco-labelling schemes, have great potential to affect a broader range of actors, among them consumers and other end-users, they suffer from several shortcomings, particularly when it comes to transparency and accountability. In addition, both public and private law instruments are challenged by the immaturity and complexity of the methodologies currently employed, such as life cycle assessment (LCA). This is apt to lead these legal tools to have a limited ability to establish the actual environmental impacts of different types of plastics, and thus properly contribute to sustainable and circular practices. We argue that to be effective in guiding stakeholder behaviour towards sustainability, these legal tools should be accountable, transparent, and backed up by adequate scientific evidence on the environmental impacts of plastics throughout their life cycle. We propose that such evidence could be obtained through holistic LCA that is based on harmonized international standards.Peer reviewe